1. Field of the Invention
The present invention relates to a vehicle seat assembly and more particularly to a vehicle seat assembly in which a seat cushion angle of a seat cushion is adjustable.
2. Description of the Related Art
Seat assemblies with reclining mechanisms to be used for automotive rear seats or the like have been known in the art. Such a seat assembly comprises a seat cushion having a seat surface on which an occupant sits and a seat back for supporting the occupant's back. In a typical seat assembly with a reclining mechanism, the seat cushion slides forward by the occupant's operation and the seat back interconnected to the seat cushion is drawn and moved by the seat cushion to define a reclining angle (for example, refer to Japanese Unexamined Utility-Model Application Publication No. 2-89947, hereinafter referred to as a Related Art Reference).
The seat assembly disclosed in the above Related Art Reference comprises a seat cushion whose position can be adjusted in the forward and backward directions of the vehicle body and a seat back having an upper seat back and a lower seat back. The lower seat back is pivotably interconnected to the rear end of the seat cushion at the lower end thereof and its rear top end is disposed slidably in the up-down direction of the vehicle body. The upper seat back is pivotably interconnected to the lower seat back at the lower end thereof and is disposed slidably in the up-down direction of the vehicle body. According to the seat assembly of the Related Art Reference, the seat cushion is drawn forward so that the interconnected lower seat back and upper seat back move together to define the reclining angle of the seat back.
If the seat cushion slides forward in parallel as in the seat assembly in the Related Art Reference, a phenomenon so-called hip-sliding that the occupant's hip slides forward as his or her upper body leans backward is provoked so that the seat assembly may not be able to provide an appropriate comfortable position.
To prevent such a hip-sliding, some types of seat assemblies have been proposed: one of them employs a curved seat rail and slides the seat cushion along the curved seat rail to raise the front end of the seat surface and change the seat cushion angle; and another one employs a different device to raise the front end of the seat cushion to change the angle of the seat cushion.
The above-described seat assemblies which prevent the hip-sliding as the seat cushions slide forward are advantageous because the occupants can keep their comfortable relaxing positions. However, special shaped parts such as the curved seat rail are required so that the manufacturing cost increases. In case that an individual device is used, increase of the number of components will cause increase in the weight in addition to increase of the manufacturing cost as a matter of course. The increase in the weight may cause an undesired influence to the fuel consumption for the vehicle with the seat assembly mounted thereon. Moreover, the space in the vehicle is limited so that a configuration is required to be fitted in a smallest space as possible.